Alcoholism and the Reward Pathway

Despite what you may have thought, alcoholism, like all addiction, begins in an area of the brain called the reward pathway.

The brain is composed of neurons that pass electrical and chemical signals across the brain’s synapses. Neurons come in different shapes and sizes which enables them to communicate in a variety of functions; when the neurons fire in a series from one area of the brain to another it creates a pathway.

In the middle of the brain is the reward pathway which includes the ventral tegmental area (VTA), the nucleus accumbens, and the prefrontal cortex. The neurons in the VTA contain dopamine, the neurotransmitter, which is in the nucleus accumbens and prefrontal cortex. Dopamine is present in the areas of the brain which control emotion, movement, cognition, motivation and pleasure.

When the pathway is activated it provides positive reinforcement, called a reward, for performing certain behaviors. There are both natural (food, water, sex, and nurturing) as well as artificial (drugs including alcohol) rewards. Overstimulation of this system produces a euphoric effect which people try to repeat.

The reward pathway enables us to feel good when we do things that are necessary for survival such as drinking, eating, or procreating. The pathway connects to several areas in the brain to allow them to gather external information (gained from the five senses) which strengthens the circuits controlling desirable behavior.

Dopamine, one of many chemical neurotransmitters, is released when you perform a desirable activity. This provides a sense of pleasure which is the reward for doing that action. The reward pathway also encourages you to repeat the same behavior by connecting areas of your brain controlling memory and behavior with it. These actions, when repeated over time, will ensure our survival when related to eating, drinking, or procreating.

Besides the reward (or mesolimbic) pathway, an over abundance of dopamine will also affect the nigrostriatal and tuberoinfundibular pathways. The nigrostriatal pathway controls motor function which may explain why alcoholics lose motor coordination. The tuberoinfundibular pathway affects the maternal instinct (or nurturing) and sensory processes. Besides affecting reward and desire, dopamine in the reward pathway will also affect memory and can be a major contributor to hallucinations and schizophrenia if the pathway is not functioning problem.

Other neurotransmitters affected by alcoholism include epinephrine, GABA, acetylcholine, glutamate and serotonin. These neurotransmitters are thought to produce a sense of well-being, however increasing dopamine levels does seem to be the product of repeated alcohol or drug use. After long periods of use, the prefrontal cortex initiates behaviors such as drinking, drugging, gambling, overeating, promiscuity, pornography, thrill seeking, and violence, which are the result of reduced inhibitions.

Alcohol, like any drug, alters the brain’s reward pathway by causing dramatic changes to the synapses in the brain once the alcohol enters the body. It bypasses the stimulus required by the five senses, although taste and smell may be involved, and directly accesses the brain’s reward pathway which provides an intense sensation of pleasure.

Alcoholism, or alcohol addiction, is the state in which a person engages in compulsive behavior even if they will have to face negative consequences. Due to the increased levels of dopamine in the reward pathway, there is a loss of control pertaining to self-limiting the addictive substance.

Alcoholism does more than affect the reward pathway of the brain; it can adversely affect the long-term health of the brain. Other neurotransmitters are affected by alcohol’s presence in the body. Alcohol use and abuse can impair learning as well as cognitive function, higher brain function (problem solving and decision making), as well as memory and movement.

Over time, with repeated use, a person may develop a certain amount of tolerance for alcohol. Because of the amount of dopamine released into the brain, the brain must adapt; one way is to reduce the number of receptors at the synapse that receive dopamine to inhibit the surge of dopamine in their system. This means the person will no longer receive the “reward” of feeling pleasure when they drink the same amount of alcohol. To achieve that same level of pleasure, the person must now drink more alcohol or a harder alcohol or drug. This is called “tolerance” and is partially responsible for addictive behavior. The longer one engages in this activity the more the receptors are reduced, thus more and more alcohol or drugs will be required to achieve the high.

With repeated use, dependence on alcohol develops. The neurons in the brain literally become dependent on the alcohol or drug of choice to function normally. They can no longer produce or release neurotransmitters like dopamine without the presence of alcohol or the drug of choice. When alcohol or the drug of choice is not present in the system, then depression and withdrawal occur and the user returns to the drink or drug to bring neurotransmitters back to their normal level and provide them with relief. As other areas of the brain outside the reward pathway that control memory, learning and judgment become impacted, the user loses their ability to regulate self-discipline and good decision making. The user is now addicted or dependent to alcohol or their substance of choice

Although we’re talking about the relationship between the reward pathway and alcoholism in this article, this is the basic way that addiction to any substance or activity occurs. Successful recovery from alcoholism, or any addiction, can be achieved by restoring balance to the neurotransmitters with diet, nutritional supplements and lifestyle changes.